Anthocyanin accumulation in strawberry fruits as affected by nitrogen nutrition

Effects of nutrient deficiency (N, P and K) on color development and anthocyanin accumulation in strawberry fruit were determined. In fruits of N deficient 'Nyoho' red color began to develop faster, while L* value and hue angle were lower at 24 days after anthesis (DAA) compared to those of control or P and K deficient plants, but there was no significant difference at 27 to 36 DAA. The concentration of total anthocyanins was significantly higher in N deficient fruits than that in control at 24 DAA, but was significantly lower in N deficient fruits compared to that in controls at 33 or 36 DAA. In case of 'Toyonoka', there was no effect of treatment on color development and anthocyanin concentration. In three other cultivars (Tochiotome, Sachinoka and Hokowase), L* value, hue and chroma were significantly higher, and the concentration of total anthocyanins was also lower in N deficient fruits compared to the other treatments. It was concluded that the anthocyanin synthesis in strawberry fruits may be reduced by N deficiency.